1. Field of the Invention
This invention pertains to a method and apparatus for cooling of electrical equipment with electromechanical refrigeration and forced air cooling.
2. The Prior Art
There are several commercially available electromechanically refrigerated cooling machines for cooling electronic enclosures and electronic equipment. Such machines have been continually used from about 1970 to date.
The particular cooling machine being discussed is generically referred to in the industrial community as a "rack mount" air conditioner or climate controller. Applicant McLean Midwest Corporation has been in this business for several years and presently offers a product line comprising Models HB11 and HB16 in 2, 3, 4, 5, 6, & 7000 BTU/hour outputs for rack mounting inside a cabinet near the top. McLean also offers its Models LB11, LB12, and LB14 and LB16 in 2, 3, 4, 5, 6, & 7000 BTU/hour outputs for rack mounting inside a cabinet near the bottom. McLean has amongst these models and outputs three (3) entirely different basic designs and seventeen (17) specific models which then further divides into voltages and so forth. It will be apparent that one of the significant problems with this type of device is the multiplicity of devices required in order to satisfy the needs for various physical configurations and directing of the cooling effort up, down, and/or transversely.
The existing devices do not, by today's improved standards and increased expectations of excellence provide sufficient thermal separation of the heated and the cooled air streams and there is a disadvantageous loss of thermal efficiency due to unwanted heat transfer.
Serviceability has become a problem because it has become apparent that both the condenser blower motor and the evaporator blower motor will fail and need replacement at least once during the life of the device. If replacement of these blower motors is difficult, the entire unit will be prematurely scrapped.
It has also been found that greater volume flows of cooled air are desirable, and that the device must fit in and to an ever increasing variety of cabinets and enclosures. It has also been found that more powerful condenser blowers are required in this type of device to meet ever more stringent ambient temperature conditions.
Much of the foregoing is influenced by the conversion from R-12 to R-22 refrigerant, for environmental benefit.